109 research outputs found

    Adenosine-mono-phosphate-activated protein kinase-independent effects of metformin in T cells

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    The anti-diabetic drug metformin regulates T-cell responses to immune activation and is proposed to function by regulating the energy-stress-sensing adenosine-monophosphate-activated protein kinase (AMPK). However, the molecular details of how metformin controls T cell immune responses have not been studied nor is there any direct evidence that metformin acts on T cells via AMPK. Here, we report that metformin regulates cell growth and proliferation of antigen-activated T cells by modulating the metabolic reprogramming that is required for effector T cell differentiation. Metformin thus inhibits the mammalian target of rapamycin complex I signalling pathway and prevents the expression of the transcription factors c-Myc and hypoxia-inducible factor 1 alpha. However, the inhibitory effects of metformin on T cells did not depend on the expression of AMPK in T cells. Accordingly, experiments with metformin inform about the importance of metabolic reprogramming for T cell immune responses but do not inform about the importance of AMPK

    Metformin as an Adjunctive Therapy for Pancreatic Cancer: A Review of the Literature on Its Potential Therapeutic Use

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    Pancreatic ductal adenocarcinoma has the worst prognosis of any cancer. New adjuvant chemotherapies are urgently required, which are well tolerated by patients with unresectable cancers. This paper reviews the existing proof of concept data, namely laboratory, pharmacoepidemiological, experimental medicine and clinical trial evidence for investigating metformin in patients with pancreatic ductal adenocarcinoma. Laboratory evidence shows metformin inhibits mitochondrial ATP synthesis which directly and indirectly inhibits carcinogenesis. Drug–drug interactions of metformin with proton pump inhibitors and histamine H2-receptor antagonists may be of clinical relevance and pertinent to future research of metformin in pancreatic ductal adenocarcinoma. To date, most cohort studies have demonstrated a positive association with metformin on survival in pancreatic ductal adenocarcinoma, although there are many methodological limitations with such study designs. From experimental medicine studies, there are sparse data in humans. The current trials of metformin have methodological limitations. Two small randomized controlled trials (RCTs) reported null findings, but there were potential inequalities in cancer staging between groups and poor compliance with the intervention. Proof of concept data, predominantly from laboratory work, supports assessing metformin as an adjunct for pancreatic ductal adenocarcinoma in RCTs. Ideally, more experimental medicine studies are needed for proof of concept. However, many feasibility criteria need to be answered before such trials can progress

    Incidence and mortality of incidental prostate cancer: a Swedish register-based study

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    In a national register-based study of incidence trends and mortality of incidental prostate cancer in Sweden, we found that a significant proportion (26.6%) of affected men diagnosed died of their disease, which challenges earlier descriptions of incidental prostate cancer as a non-lethal disease

    Functional Interaction of Nuclear Domain 10 and Its Components with Cytomegalovirus after Infections: Cross-Species Host Cells versus Native Cells

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    Species-specificity is one of the major characteristics of cytomegaloviruses (CMVs) and is the primary reason for the lack of a mouse model for the direct infection of human CMV (HCMV). It has been determined that CMV cross-species infections are blocked at the post-entry level by intrinsic cellular defense mechanisms, but few details are known. It is important to explore how CMVs interact with the subnuclear structure of the cross-species host cell. In our present study, we discovered that nuclear domain 10 (ND10) of human cells was not disrupted by murine CMV (MCMV) and that the ND10 of mouse cells was not disrupted by HCMV, although the ND10-disrupting protein, immediate-early protein 1 (IE1), also colocalized with ND10 in cross-species infections. In addition, we found that the UL131-repaired HCMV strain AD169 (vDW215-BADrUL131) can infect mouse cells to produce immediate-early (IE) and early (E) proteins but that neither DNA replication nor viral particles were detectable in mouse cells. Unrepaired AD169 can express IE1 only in mouse cells. In both HCMV-infected mouse cells and MCMV-infected human cells, the knocking-down of ND10 components (PML, Daxx, and SP100) resulted in significantly increased viral-protein production. Our observations provide evidence to support our hypothesis that ND10 and ND10 components might be important defensive factors against the CMV cross-species infection

    SUMO Pathway Dependent Recruitment of Cellular Repressors to Herpes Simplex Virus Type 1 Genomes

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    Components of promyelocytic leukaemia (PML) nuclear bodies (ND10) are recruited to sites associated with herpes simplex virus type 1 (HSV-1) genomes soon after they enter the nucleus. This cellular response is linked to intrinsic antiviral resistance and is counteracted by viral regulatory protein ICP0. We report that the SUMO interaction motifs of PML, Sp100 and hDaxx are required for recruitment of these repressive proteins to HSV-1 induced foci, which also contain SUMO conjugates and PIAS2β, a SUMO E3 ligase. SUMO modification of PML and elements of its tripartite motif (TRIM) are also required for recruitment in cells lacking endogenous PML. Mutants of PML isoform I and hDaxx that are not recruited to virus induced foci are unable to reproduce the repression of ICP0 null mutant HSV-1 infection mediated by their wild type counterparts. We conclude that recruitment of ND10 components to sites associated with HSV-1 genomes reflects a cellular defence against invading pathogen DNA that is regulated through the SUMO modification pathway

    Catalysing sustainable fuel and chemical synthesis

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    Concerns over the economics of proven fossil fuel reserves, in concert with government and public acceptance of the anthropogenic origin of rising CO2 emissions and associated climate change from such combustible carbon, are driving academic and commercial research into new sustainable routes to fuel and chemicals. The quest for such sustainable resources to meet the demands of a rapidly rising global population represents one of this century’s grand challenges. Here, we discuss catalytic solutions to the clean synthesis of biodiesel, the most readily implemented and low cost, alternative source of transportation fuels, and oxygenated organic molecules for the manufacture of fine and speciality chemicals to meet future societal demands

    International Consensus Statement on Rhinology and Allergy: Rhinosinusitis

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    Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods: ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion: This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS

    Role of cyclin D1 in conferring malignant phenotypes on immortalized esophageal epithelial cells

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    Cyclin D1 is commonly overexpressed in many types of human squamous cell carcinomas, including esophageal squamous cell carcinoma. Studies in the past mainly focused on the role of cyclin D1 in cell growth and regulation of the G1/S transition of the cell cycle. Recently, malignant transformation induced by classical oncogenes was shown to be associated with upregulation of cyclin D1. So far, there are still no reports on the direct contribution of cyclin D1 to malignant transformation of immortalized epithelial cells. In this study, the role of cyclin D1 in the early stage of esophageal carcinogenesis was investigated by stable overexpression of cyclin D1 in an hTERT-immortalized esophageal epithelial cell line, NE2-hTERT. Our results showed that ectopic expression of cyclin D1 stimulated anchorage-independent growth in soft-agar, which is a major hallmark of transformed cells. This finding was further supported by the decrease in colony number in an esophageal cancer cell line (KYSE510) with cyclin D1 knockdown by siRNA. Cyclin D1 overexpressing esophageal epithelial cells also acquired a higher ability to migrate through cellular matrix, and showed reduced adhesion to different substrates. Western blotting and pull-down assays were used to further explore the mechanism involved. The results showed that the overexpression of cyclin D1 was associated with upregulation of pERK1/2 and reduced Rac1 activity. Our findings suggest that cyclin D1 overexpression promotes invasive potential and migration ability in immortalized esophageal epithelial cells, and that these malignant phenotypes may be mediated by pERK1/2 and cytoskeletal signaling. [This study is supported by the Research Grants Council of the Hong Kong SAR, China (Central allocation Project No. HKUST 2/06C)

    Nonlocal dispersal and averaging in heterogeneous landscapes

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    While reaction–diffusion equations are the standard modelling framework for many questions in spatial ecology, their nonlocal analogues, integrodifferential equations, have gained in popularity recently. Here we consider integrodifferential equations for population spread and persis-tence in heterogeneous landscapes, and we develop appropriate averaging methods for these models. We average over landscape and patch scales. While averaging methods for reaction–diffusion equations lead to relatively simple expressions of persistence conditions and invasion speeds, we find that the results are much richer and more complicated for integro-differential equations. We illustrate our results with two dispersal mechanisms: (1) individuals are mobile throughout their lifetime and (2) only offspring move
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